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How To Shrink Rubber O Ring [Answered]

Rubber o rings are an essential part of any piping project. But overuse of an o ring can leave it in a state where it is expanded. So, shrinking it down to its original size is necessary. It can be tough work to see through.

How to shrink rubber o ring?

The shrinking process can be done using a few methods as rubber is quite malleable. The use of hot or boiling water can help. Using a hairdryer is also advisable. Using a method based on the rubber is important

The following article will discuss in detail the procedures. Using this you would be able to shrink a rubber o ring. All the methods below can be done at home.

How To Shrink Rubber O Rings

Rubber is a thermoplastic polymer that is used to build everything. From gloves and phone covers to rubber bands and gaskets. Rubber o rings especially can get stretched as they are used while fitting water pipes, hoses, etc. 

And all other rubber products can face the same issue. These items become stretched out over time and no longer function properly. We’ll show you how to reconstruct the normal form and size of rubber o rings.

Hot Water Method

Hot water is a great way to shrink a rubber o ring. Rubber is a material that has molecules that get congested if exposed to heat. So, in layman’s terms, any rubber product will shrink if exposed to heat.

So to shrink your o ring you can either use hot water directly or pour it over the ring. It is advised to use a gas water heater instead of an electric one. As the temperature can be easily controlled.

Or use a bowl of water and insert it slowly. Using a hot towel soaked with water will do as well. It is advised to use a bowl or hot towel as you will have more control over the ring.

We have suggested some good water heaters:

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After using hot water you will notice the o ring to have shrunk significantly. But keep in mind the rubber molecules will expand a little after removing them from the heat. So, shrink the rubber o ring more than the desired size. 

Therefore, if it expands a little, you will have your desired size. Using this process is one of the safer and simpler ones.

Boiling Water Method

If the hot water method doesn’t work. It may be because the type of rubber in the o ring is too tough for that particular temperature. So, the next best thing is the boiling water method. 

Take a pot full of water. Put it over a heat source and wait for it to start boiling. When the water starts boiling, put in the rubber o rings gently. Using tongs for this is advised. 

After a couple of minutes, you will see that the rings have started to shrink. Keep a close eye on the rings and the pot. Safety should be ensured as any task involving high temperatures is risky.

One thing to keep in mind is that using boiling water can be troublesome. Firstly, using boiling water is dangerous and can be harmful. So, you must be careful. 

And secondly, if the rubber in the o ring isn’t strong enough it might start to melt. But if your water heater has a plastic cap or surface, it means the temperatures are not high enough. So no need to worry about melting the rings.

So, keeping these things in mind, the use of boiling water to shrink rubber o rings is a viable option.

Hairdryer Method

If you want to avoid water entirely you can use a regular hair dryer to get the same result. Though it works better with thin rubber materials like gloves and such. O rings can also be shrunk by a hairdryer. 

To do this you must take off the cap of the hairdryer( if it has any) so that the heat is distributed evenly. Then you can gradually apply heat and model the o ring to a shrunken state. Or the correct size you are looking for.

And similar to any process of shrinking rubber try to keep the size in mind. You’ll see that the o ring has decreased somewhat. 

This method is quite harmless. But the drawback is that this method takes a significant amount more time. So, anyone valuing safety over time can use this method. 


Question: What is the best material for an O ring?

Answer: O-rings are made of materials like PTFE, Nitrile (Buna), Neoprene, EPDM Rubber, and Fluorocarbon (Viton). Silicone seals and Kalrez o-rings are also commonly utilized in high-temperature applications.

Question: What is the best way to extend a ring?

Answer: Using a mandrel and a mallet is one of the simplest and easy techniques to stretch a ring. When the ring has any mounted jewels or diamonds. This method works best for scaling only a modest amount and should be utilized with utmost caution.

Question: What is the best way to shrink a rubber gasket?

Answer: Heat the rubber material with a blow drier or hot air gun outside. The rubber should be hung. Hang the rubber band or object away from your clothing and skin from a hook or nail on an outside wall or structure. Stretch the rubber material with a weight or a heavy object before it shrinks.


That’s all there is to know about how to shrink rubber o ring. We expect that this article was up to your standards. These were simple remedies that did not require the assistance of an expert.

Best wishes until the next time!